In recent years, semiconductor devices have been developed to be used as an LSI, a CPU, or a memory. A CPU is an aggregation of semiconductor elements each provided with an electrode which is a connection terminal, which includes a semiconductor integrated circuit (including at least a transistor and a memory) separated from a semiconductor wafer.
A semiconductor circuit (IC chip) of an LSI, a CPU, or a memory is mounted on a circuit board, for example, a printed wiring board, to be used as one of components of a variety of electronic devices.
In addition, a semiconductor device capable of transmitting and receiving data has been developed. Such a semiconductor device is called a wireless tag, an RFID tag, or the like. Those put into practical use include a semiconductor circuit (IC chip) formed using an antenna and a semiconductor substrate in many cases.
A silicon-based semiconductor material has been known as a semiconductor material that can be used for a transistor; however, an oxide semiconductor has attracted attention as another material. As a material of the oxide semiconductor, zinc oxide or a substance containing zinc oxide is known. In addition, a transistor including an oxide semiconductor having an electron carrier concentration of lower than 1018/cm3 is disclosed (Patent Documents 1 to 3).